1. Field of the Invention
The present invention relates to a sheet material for use in the electrographic printing wherein the sheet material is prepared by treatment with a water-soluble conductive substance. More particularly, it relates to sheet materials with electroconductive water-soluble quaternary resin comprising at least one member of the group of polymers having recurring units of the general formula: ##EQU1## wherein: 1. X is a halogen selected from the group consisting of chlorine and bromine;
2. A is a divalent radical selected from the group consisting of 1,4-butene-2-yl and 1,4-cyclopentene-2-yl radicals optionally substituted with chloro, methyl or ethyl radicals; PA1 3. N is a nitrogen atom; PA1 4. R is a divalent radical selected from the group consisting of phenylene, xylylene and saturated and unsaturated alkylene radicals of 2 to 6 carbon atoms optionally substituted with methyl and hydroxyl radicals; PA1 5. Y is a radical selected from the group consisting of C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.4 hydroxyalkyl, and when R is an ethylene radical, methylene so that the Y radicals form an ethylene bridge between the nitrogen atoms connected by R; PA1 6. z is a radical selected from the group consisting of C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.4 hydroxyalkyl, and when R is an ethylene radical, methylene so that the Z radicals form an ethylene bridge between the nitrogen atoms connected by R; and PA1 7. The degree of polymerization of the resin is such that the resin has an intrinsic viscosity of at least 0.05 in 2 percent aqueous sodium chloride at 25.degree.C. PA1 2. A is a divalent radical selected from the group consisting of 1,4-butene-2-yl and 1,4-cyclopentene-2-yl radicals optionally substituted with chloro, methyl or ethyl radicals; PA1 3. N is a nitrogen atom; PA1 4. R is a divalent radical selected from the group consisting of phenylene, xylene and saturated and unsaturated alkylene radicals of two to six carbon atoms optionally substituted with methyl and hydroxyl radicals; PA1 5. Y is a radical selected from the group consisting of C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.4 hydroxyalkyl, and when R is an ethylene radical, methylene so that the Y radicals form an ethylene bridge between the nitrogen atoms connected by R; PA1 6. z is a radical selected from the group consisting of C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.4 hydroxyalkyl, and when R is an ethylene radical, methylene so that the Z radicals form an ethylene bridge between the nitrogen atoms connected by R; and PA1 7. The resin D.P. is such that the resin has an intrinsic viscosity of at least 0.05 in 2 percent aqueous sodium chloride at 25.degree.C.
2. The Prior Art
Electrographic printing processes require composite sheet materials comprising an electrically insulating layer on an electrically conductive layer. The electrically conductive layer should possess a surface resistivity of no more than about 1 .times. 10.sup.10 to 1 .times. 10.sup.8 ohms over a relative humidity range of about 25 to 80 percent in order to be useful. During the printing process, the sheet material is grounded by placing it on a grounded electrical conductor so that, in effect, the lower surface of the electrically insulating layer is grounded to the conductor on which the sheet material rests, through the electrically conductive layer. The requirement of good electrical conductivity in the conductive layer is a source of major difficulty in securing uniformly satisfactory performance with dielectric and photoconductive reproduction papers under different climatic conditions of humidity and temperature. Much effort has been expended to develop a conductive sheet material which will exhibit a high degree of electroconductivity under varying environmental conditions of temperature, relative humidity, sheet moisture, etc., as well as under the varying operating conditions which are encountered from one copying process and machine to the next.
Various means have been described for increasing the conductivity of sheet material which is used in dielectric and photoconductive printing processes. Such means, while representing valuable contributions to the art, have certain drawbacks which detract from their overall usefulness. These drawbacks include loss of conductivity under conditions of varying humidity, poor aging properties, poor hold-out against solvent based resins used to coat the sheet material, migration of the conductive material in the sheet, difficulty of preparation, undesirable odors, etc.
Polyvinyl alcohol provides a particularly effective treatment for solvent hold-out. Unfortunately, none of the presently available electroconductive resins is compatible with polyvinyl alcohol. Incompatibility is shown inter alia by a pronounced decrease in conductivity when the electroconductive resin is blended with the polyvinyl alcohol and applied to the sheet material.
A definite need exists for a water-soluble conductive material for treating sheet material used in dielectric and photoconductive printing processes which will maintain a high electroconductivity under widely varying conditions of temperature and humidity. A further need exists for an electroconductive material which will be compatible with polyvinyl alcohol and other paper-making additives. A further need exists for an easily prepared water-soluble electroconductive material which can be used to treat sheet material used in dielectric and photoconductive processes.